hydrogen bond

A form of association between an electronegative atom and a hydrogen atom attached to a second, relatively
electronegative atom. It is best considered as an electrostatic interaction, heightened
by the small size of hydrogen, which permits proximity of the interacting dipoles
or charges. Both electronegative atoms are usually (but not necessarily) from the
first row of the Periodic Table, i.e. N,
O
or F.
Hydrogen bonds may be inter-molecular or intramolecular. With a few exceptions, usually involving fluorine, the associated energies are less
than
-
(
-
).